This made me think of how sometimes I think I see someone's shadow, but then am not sure.

I was standing at the copy machine at an old building a few months ago and felt someone behind me. I turned and no one was there. I walked out into the hallway and it was empty. I asked a woman who works there, "Do you have ghosts?" She said, "Did you feel someone standing behind you? You need to talk to Jane." Turns out that Jane feels a presence all the time, too. :)

Lynn~ This has happened to me the last few weeks up here! I'll have the sense that there's a presence like in my peripheral vision and then perhaps behind me...but upon turning...nothing. It's a bit more unnerving at dusk or in the fog or the mist. I have tried very hard to face & to overcome my fear of being alone in the woods (as I now live in the midst of them) and almost all of the time now I enjoy the solitude!